There are a few complete ones that are OK, relatively speaking. They're all pretty short and there aren't that many stories from pre-classical Egypt, so if you're interested, I'd say track them down and give them a try, but don't expect easy reads. I guess part of why I favor those two, especially the latter, is that I can imagine they might become great, when whole.
It's probably not what GP was thinking of because it's not relatively late and reasonably complete, but Sinuhe is probably the greatest surviving work of Middle Egyptian fiction.
